Referring to FIG. 1, a conventional extrusion molding die 1 comprises a female mold 11 which a hole 111 is formed therein and a post 12 insertedly disposed in the female mold 11. The post 12 presses against a metal blank 100 disposed in the female mold 11 such that the metal blank 100 passes through the hole 111 of the female mold 11 to form a slender metal workpiece 101.
Referring to FIGS. 1, 2, metal flow lines 102 of the slender metal workpiece 101 manufactured with the extrusion molding die 1 are continuous. Hence, the slender metal workpiece 101 displays satisfactory mechanical properties, mechanical strength and thus is widely used in the manufacturing of mechanical parts and components which have strict safety requirements.
However, with the metal flow lines 102 being linear, the slender metal workpiece 101 has poor damping capacity. In view of this, it is important to improve the slender metal workpiece 101 in terms of mechanical properties, mechanical strength, and damping capacity.